Galvanizing-bath.



N. K. TURNBULL.

GALVANIZING BATH.

APPLICATION FILED FEB.17. 1915.

Patented Aug. 31, 1915.

LID

PATENT Fl li@e NICHQLAS KING TURNB'ULL, 0F MANCHESTER, ENGLQND.

GALVANIZING-BATH.

To all whom it may concern:

Be it known that I, NICHOLAS KING TURNBULL, a subject of the King ofGreat Britain, residing at 3v York street, Manchester, in the county ofLancaster, England, have invented new and useful Improvements inGalvanizing-Baths, of which the following is a specification.

This invention has for its object means for insuring that-wire, strips,sheets or like objects may be galvanized without passing through anaccumulation of impure spelter or dross, and is adapted for use in bathswhere zinc is superimposed on a metal of higher specific gravity, suchas lead.

Baths containing only molten zinc are in general use, even though it isrecognized that excessive losses take place due to the formation of hardspelter or dross (by contact of molten zinc and iron) produced by themore or less rapid deterioration of the bath and of the guides, forksand rollers therein, and by the material itself being wholly in contactwith molten zinc during its entire passage through the bath.

It has been recognized that the combined use of lead and zinc ofiers ameans of reducing the formation of impure spelter or dross, but themethods hitherto adopted have had serious drawbacks, as only acomparatively thin layer of spelter of uniform depth has beensuperimposed on lead, the material to be galvanized in some casesentering the bath through lead only, andin others through spelter andthen into the lead, but in all cases necessarily being fin ished throughspelter. In all these cases the actual time in zinc has been greatlyreduced over ordinary practice, with a consequent reductlon in theformation of dross, but such dross as has been made from the materialitself, is made and necessarily accumulates at the very worst place,viz: at the exit end, and in the path of the material; and the troubleas a rule has been intensified by the use of iron guides or boxes at thesame place, while no provisionhas been, or could specification ofLetters Patent.

Patented Aug. an, 1e15,

Application filed February 17, 1915. Serial No, 8,891.

has been suggested, between the baths being filled with lead, the innerbath being filled with spelter, with a layerof spelter above the sameextending more or less to the sides of the exterior bath, it beingcontended that the dross formed between the baths would automaticallyfall into the smaller bath. This, however, is impossible; dross would beformed from the sides of the baths, and from the material beinggalvanized, and as formed would fall vertically down and accumulate inthe outgoing path of the material being galvanized, to an extent thatwould prove troublesome and detrimental and leave the coating not equalin quality to the product from an all zincbath.

Now the present invention difi'ers from these and any known efforts byheating the spelter solely through the lead, and ininsuring that whilethe material being gal vanized passes through a very limited path ofspelter it still enters and finishes through spelter-having asubstantial depth. This is a matter of prime importance, as only with afair depth of zinc is the purity of the top layer of spelter secured,and at the same time the material passes preferably at an angle over theend chambers containing a fair depth of zinc, and close to thepartitions into and out of the central lead chamher, in such manner thatthe impure spelter formed falls vertically and is collected in saidchambers, below the path of and away from the material being galvanized.These end and specially arranged chambers or receptacles at the ingoingand outgoing ends, have suflicient capacity to receive any desiredquantity of dross, so as to, enable the work to proceed for aconsiderable time, such as a week, without interruption.

To enable the invention to be thoroughly understood, reference is madeto the accompanying drawings, in which Figure 1 represents a sectionalelevation of a bath embodying the features herein set forth, and Fig. 2is a plan of the bath shown in Fig. 1.

The bath B is made in accordance with known practice, but has twodividing partitions D of desired depth, welded or otherlead L to theheight 'of said partition D,

and the two outer compartments also with lead to a lesser depth. Zinc Zis provided (say for example Wires W) is directed at an angle, and closeto the entering partition,

so that any impure zinc formed falls to the lowest depth of zincavailable (due to its greater specific gravity) such impure zinc, whichultimately forms hard spelter or dross, being collected away from thepath of the material being galvanized. The material W then passesthroughthe central lead.

portion of the bath, and then close to the partition through thefinishing layer of zinc at the outgoing end of the bath. It will beobvious that owing to the forward movement of the material, impure zinccannot accumulate at the portion where the material enters the finallayer of zinc, but such impure zinc will be continuously directed insuch a manner as will effectually insure the same falling in the greaterdepth of zinc in the outer finishing compartment.

An additional division. or barrier R is preferably also inserted whollyor partially across the bath in the upper layer of zinc, to provide arestricted passage at the point where the material being galvanizedpasses the division of last compartment, to prevent any dross that maybe floating on the highest level of lead from getting'into the path ofthe material being galvanized, and with the object of still furtherinsuring that no impure spelter or dross may accumulate in the path ofthe material. Such a division also may be inserted in a correspondingposition at the entering end, asshown.

The invention is also applicable to baths for galvanizing otherarticles, say for example sheets, strips, nettings, tubes, or othermaterial that can .be passed continuously through the bath, thearrangement being such that the baths can be worked for any convenientperiod due to this invention providing efiective means for continuouslydiverting the impure spelter from the path of the material beinggalvanized, thus insuring a covering of the purest spelter thereon.

1. In baths for galvanizing with zinc superposed on a heavier metal suchas lead, and where the zinc is wholly heated through the lead: incombination, an outer casing for the metal; dividing members separatingthe interior of said easing into three compartments, said members beingsecured to the bottom and sides of said casing, and extending from thebottom to a level short of the top thereof; the inner of saidcompartments being filled with metal such as lead, and the outer or endcompartments containing such metal to a lesser depth; molten zinc beingsuperposed onthe lead; and means for guiding the article to begalvanized through the bath, above the outer and into and out of theinner of said compartments, close to the dividing members, for thepurpose and substantially as herein set forth.

2. In baths for galvanizing with zinc superposed on a heavier metal suchas lead, and where the zinc is wholly heated through the lead; incombination, an outer casing for the metal; dividing members separatingthe interior of said casing into three compartments, said members beingsecured to the bottom and sides of said casing, and extending from thebottom to a level short' of the top thereof; the inner of saidcompartments being filled with metal such as lead, and the outer or endcompartments containing such metal to a lesser depth, molten zinc beingsuperposed on the lead; an upper barrler adjacent to one of saiddividing members and extending across said casing at the upper portiononly; and means for guidmg the article to be galvanized, through thebath, above the outer of said compartments, and between said barrier andits adjacent dividing member, and into and out of the inner of saidcompartments, close to said dividing members, for the purpose andsubstantially as herein set forth.

In testimony whereof I have signed 'my name to this specification in thepresence of two subscribing witnesses.

NICHOLAS KING TURNBULL.

